Tag Meta is a native extension (component + plugin) available for Joomla that allows to efficiently manage all site's meta information. With Tag Meta, as example, it is possible to set the tag 'title' or the meta tags (e.g. from the most common 'description', 'keywords', 'author', 'robots', as well as the recently 'content rights' and 'external reference') or link 'canonical' on any page, just specifying the URL or a part of it. This provides a swiss army knife to improve site positioning in SEO optimization. But Tag Meta also supports regular expressions in the matching rules and this allows to match a group of URLs with a single rule. In this way it is possible to manage all metadata from a single control panel.

Multiple rules can be applied together, so if more than a single rule matches with the current URL, these are applied in cascade using the ordering set, except if a rule is declared as ‘last one’ (in this case the process stop).

And that’s not all. Tag Meta comes with support for macros. This means that meta information can be generated dynamically for each page (e.g. there's a fantastic 'autokeywords' and ‘autokeywords2’ macro - Enterprise version only - that allow to extract automatically the most relevant words from a page content).

To allow complex transformations for data to use as meta info there are the placeholders. Placeholders allow you to define a set of values where each value is associated and identified by a name and is used in the definition of other placeholders or in the definition of meta info (practically they are based on the same principle of the variables in programming languages).

The plugin, finally, has some useful options to set custom global information like Generator, Author, Copyright, or to set and align the tag ‘title’ and the meta tag ‘title’ in many ways.

There are two versions of Tag Meta, Community and Enterprise, both released under GPL license. The Community version is completely free, while the Enterprise version has a little subscription fee, but introduces some advanced features. Here's a comparison matrix between Community version and Enterprise version:

Features	Tag Meta Community	Tag Meta Enterprise
Support for tag 'title' and meta tag 'description', 'author', 'keywords', 'robots', 'content rights', and 'external reference' on each page
Support for Robots options Index, Follow, Snippet, Archive, Odp, and Image Index
Support for link 'canonical'
Support for global meta tag 'generator'
Possibility to add site name to tag 'title'
Possibility to align meta tag 'title' with tag 'title'
Possibility to preserve tag 'title' on each rule from global settings
Support for global meta tag 'author'
Support for global meta tag 'copyright'
Possibility to add a note for each item
Possibility to apply multiple matching rules
Use of regular expressions into matching rules
Case-sensitive option on the matching source URLs
Request only option to match the full URL or just the REQUEST_URI part
Decode URL option to decode URLs before to check if match with rule
Last rule option to break application of matching rule
Support for placeholders
Use of macros to specify meta info (dynamic meta info)	(46 macros)	(62 macros)
Macro {querydrop} to remove specified variables from the original query
Macro {querydropfull} to remove specified variables from the original full query
Macro {pathfrombaseltrim} to cut on left the path without the base part
Macro {pathfrombasertrim} to cut on right the path without the base part
Macro {preg_match} for apply regular expressions to full URL
Macro {preg_select} for apply regular expressions to full URL and use result to query database
Macro {autokeywords M,N} for automatic generation of keywords
Macro {autokeywords2 M,N} for automatic generation of two-words keywords
Macro {autosentence M,N} for automatic generation of sentences
Macro {synonyms} for automatic generation of synonyms based on the ontology database
Macro {nodevalue attrname,attrvalue} for extraction of any content from the document DOM
Ontology database for synonyms with automatic generation of new synonyms from existing keywords
Trace items usage with hits counter and info about last visit
Trace synonyms usage with hits counter and info about last visit
Configurable list of keywords to exclude from auto keywords generation
Possibility to remove duplicated entries from keywords
Possibility to remove the 'canonical' link if the page corresponds to the link itself
Possibility to remove duplicated entries of 'canonical' link
Possibility to set to a global base path for web site
Safe UTF-8 word count function, for old PCRE versions without UTF-8 support
REDIRECT mode, to support URL rewrite (e.g. sh404SEF) with Apache and IIS
License	GPL 2.0	GPL 2.0
Price	Free	9 €

ReDJ is a native extension (component + plugin) available for Joomla that allow to manage URL redirections. This is very useful for creating URL aliases, and managing redirections from an old URL to a new one. A very similar extension has been added into Joomla since 1.6 version (Redirect component), but ReDJ supports powerful regular expressions that allow to match more than one source URL. In this way it is possible to create a group of redirections with just one ReDJ item. It's so easy.

Also, now ReDJ comes with support for macros into destination URL. This means that from now the destination URL can be dynamic.

Finally, an "internal redirect" feature has been added (Enterprise version only). With these features now is possible to create "real" URL alias with Joomla.

There are two versions of ReDJ, Community and Enterprise, both released under GPL license. The Community version is completely free, while the Enterprise version has a little subscription fee, but introduces some advanced features. Here's a comparison matrix between Community version and Enterprise version:

Features	ReDJ Community	ReDJ Enterprise
Intercept and redirect any error 404 URL
Support for 301 (Moved Permanently)
Support for 307 (Temporary Redirect)
Support for 200 (Internal Redirect)
Use of regular expressions to specify matching source URLs
Case-sensitive option on the matching source URLs
Request only option to match the full URL or just the REQUEST_URI part
Decode URL option to decode URLs before to check if match with rule
Support for skip rule condition
Support for skip usergroup condition
Support for placeholders
Option to apply a rule only in case of error
Possibility to add a note for each item
Use of macros to specify destination URL (dynamic destination URLs)	(42 macros)	(54 macros)
Custom error page
Use of macros to customize error page	(6 macros)	(6 macros)
Trace redirections with hits counter and info about last visit
Trace custom error page with hits counter and info about last visit
Trace errors with hits counter and info about last referer and time
Trace referers for each visited URL with hits counter and info about last visit
Configurable list of referers to exclude from trace with macro support	(2 macros)	(2 macros)
Option to redirect any error 404 URL to a custom page
Option to shortcut extensions directly on the error page
Option to set a global base path (easy items portability)
License	GPL 2.0	GPL 2.0
Price	Free	9 €